A conventional distance measuring device is disclosed in U.S. Pat. No. 7,040,036 to Hui Chen Wang who is the wife of applicant and includes a wheel rotatably connected to a pole and a measuring unit is connected to a side of the wheel. The wheel includes a radius and rolls against a surface and the number of revolutions of the wheel can be counted by a counter in the measuring unit so as to obtain the distance that the wheel travels. A handle is connected to the other end of the pole and includes a brake key and an initialization key, two respective cables are connected to the brake key and the initialization key so as to brake the wheel and initialize the counter.
When using the measuring device, the counter is first initialized and the brake key is released, the user rolls the wheel on the surface and stops the wheel by operation of the brake key when the end of the distance to be measured is reached. The result of the number of revolution or the distance that the measuring device travels can be read. However, the user has to hold the brake key when reading the result and once the brake key is unintentionally released, the wheel might roll a small distance and the result will not be correct. In some situations, the user has to move the measuring device to a place where sufficient light is provided so as to read the result, the user then has to keep the brake key at the brake position for a while and this is not an easy task. The brake key can be released if an impact is applied to the device or the user slips or any unexpected situation happens.
The present invention intends to provide a brake mechanism for a wheeled distance measuring device wherein the brake mechanism can be locked to the brake position without pressing the brake key all the time when moving the measuring device.